The leg is not a straight line. A common misconception when drawing this limb is the idea that a leg that is not bent forms a straight line. This is far from the reality. One of the ways that will help with understanding the body and, therefore, the ability to draw it is thinking in mechanistic ways.

A student drawing of the legs that are
incorrectly straight.

The upper leg and the lower leg meet in a hinge. This allows for the leg to bend in one direction and stops it bending at a certain point in the opposite direction.

For the hinge to work, it needs to have a solid construction–that’s the job for the bones. They are formed in a way that supports the bending one way. Then the hinge needs to be secured in place so that the bones will not slip. That’s the job for muscles. Another set of muscles then provides the force that will bend the leg.

In early human figure drawings of my students, you’ll see what I mean. In the one at left, the model depicted was not moving, but the legs are in a position of an arrested stride. The problem we have here is that the upper and the lower leg form a straight line. This very rarely happens and when it does it is a result of an over-extension. Instead, in reality, the lower leg is kind of offset.

In the correct drawing of this pose, the upper and lower leg are offset against each other, creating a visually pleasing and anatomically correct depiction.

In another student drawing, the straight line that the upper and lower leg form is show from a posterior view, and has less of a sense of arrested movement, but still looks awkward and stiff. To correct this, the drawing needs to take into account the hinge I was describing earlier at the knee.

Student drawing,
posterior view
of legs.

Corrected drawing that takes into
account the knee hinge of the leg.

The video counterpart of this blog entry has extra content if you are interested in learning more. You can find it here. Let me know if you have any questions about drawing the leg by leaving a comment.